Table of Contents

Enum Histogram

Namespace
RocksDbNet
Assembly
RocksDb.Net.dll

A distribution collected by the statistics subsystem.

public enum Histogram

Fields

AsyncPrefetchAbortMicros = 61

Wait time for aborting async read in FilePrefetchBuffer destructor

RocksDb calls this ASYNC_PREFETCH_ABORT_MICROS.

AsyncReadBytes = 57

Stats related to asynchronous read requests.

RocksDb calls this ASYNC_READ_BYTES.

BlobDbBlobFileReadMicros = 46

Blob file read latency.

RocksDb calls this BLOB_DB_BLOB_FILE_READ_MICROS.

BlobDbBlobFileSyncMicros = 47

Blob file sync latency.

RocksDb calls this BLOB_DB_BLOB_FILE_SYNC_MICROS.

BlobDbBlobFileWriteMicros = 45

Blob file write latency.

RocksDb calls this BLOB_DB_BLOB_FILE_WRITE_MICROS.

BlobDbCompressionMicros = 48

BlobDB compression time.

RocksDb calls this BLOB_DB_COMPRESSION_MICROS.

BlobDbDecompressionMicros = 49

BlobDB decompression time.

RocksDb calls this BLOB_DB_DECOMPRESSION_MICROS.

BlobDbGetMicros = 40

BlobDB Get latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_GET_MICROS.

BlobDbKeySize = 37

BlobDB specific stats Size of keys written to BlobDB. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_KEY_SIZE.

BlobDbMultigetMicros = 41

BlobDB MultiGet latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_MULTIGET_MICROS.

BlobDbNextMicros = 43

BlobDB Next latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_NEXT_MICROS.

BlobDbPrevMicros = 44

BlobDB Prev latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_PREV_MICROS.

BlobDbSeekMicros = 42

BlobDB Seek/SeekToFirst/SeekToLast/SeekForPrev latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_SEEK_MICROS.

BlobDbValueSize = 38

Size of values written to BlobDB. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_VALUE_SIZE.

BlobDbWriteMicros = 39

BlobDB Put/PutWithTTL/Write latency. Only applicable to legacy BlobDB.

RocksDb calls this BLOB_DB_WRITE_MICROS.

BlockKeyDistributionCv = 70

Coefficient of variation of key gaps in blocks, scaled by 10000 (e.g., CV of 0.4532 is recorded as 4532). Currently only used by index blocks for uniform key distribution tracking.

RocksDb calls this BLOCK_KEY_DISTRIBUTION_CV.

BytesPerMultiget = 33

RocksDb's BYTES_PER_MULTIGET.

BytesPerRead = 31

Value size distribution in each operation

RocksDb calls this BYTES_PER_READ.

BytesPerWrite = 32

RocksDb's BYTES_PER_WRITE.

CompactionCpuTime = 3

RocksDb's COMPACTION_CPU_TIME.

CompactionOutfileSyncMicros = 6

RocksDb's COMPACTION_OUTFILE_SYNC_MICROS.

CompactionPrefetchBytes = 59

Number of bytes for RocksDB's prefetching (as opposed to file system's prefetch) on SST file during compaction read

RocksDb calls this COMPACTION_PREFETCH_BYTES.

CompactionTime = 2

RocksDb's COMPACTION_TIME.

CompressionTimesNanos = 34

RocksDb's COMPRESSION_TIMES_NANOS.

DbGet = 0

RocksDb's DB_GET.

DbMultiget = 10

RocksDb's DB_MULTIGET.

DbSeek = 15

RocksDb's DB_SEEK.

DbWrite = 1

RocksDb's DB_WRITE.

DecompressionTimesNanos = 35

RocksDb's DECOMPRESSION_TIMES_NANOS.

ErrorHandlerAutoresumeRetryCount = 56

Error handler statistics

RocksDb calls this ERROR_HANDLER_AUTORESUME_RETRY_COUNT.

FileReadCompactionMicros = 19

RocksDb's FILE_READ_COMPACTION_MICROS.

FileReadDbIteratorMicros = 23

RocksDb's FILE_READ_DB_ITERATOR_MICROS.

FileReadDbOpenMicros = 20

RocksDb's FILE_READ_DB_OPEN_MICROS.

FileReadFlushMicros = 18

Time spent in reading SST table (currently only block-based table) or blob file corresponding to Env::IOActivity

RocksDb calls this FILE_READ_FLUSH_MICROS.

FileReadGetMicros = 21

The following FILE_READ_* require stats level greater than StatsLevel::kExceptDetailedTimers

RocksDb calls this FILE_READ_GET_MICROS.

FileReadMultigetMicros = 22

RocksDb's FILE_READ_MULTIGET_MICROS.

FileReadVerifyDbChecksumMicros = 24

RocksDb's FILE_READ_VERIFY_DB_CHECKSUM_MICROS.

FileReadVerifyFileChecksumsMicros = 25

RocksDb's FILE_READ_VERIFY_FILE_CHECKSUMS_MICROS.

FileWriteCompactionMicros = 28

RocksDb's FILE_WRITE_COMPACTION_MICROS.

FileWriteDbOpenMicros = 29

RocksDb's FILE_WRITE_DB_OPEN_MICROS.

FileWriteFlushMicros = 27

Time spent in writing SST table (currently only block-based table) or blob file for flush, compaction or db open

RocksDb calls this FILE_WRITE_FLUSH_MICROS.

FlushMemtableMemoryBytes = 75

Distribution of total memtable memory usage at flush start.

RocksDb calls this FLUSH_MEMTABLE_MEMORY_BYTES.

FlushMemtableTotalDataSize = 76

Distribution of total memtable data size at flush start.

RocksDb calls this FLUSH_MEMTABLE_TOTAL_DATA_SIZE.

FlushTime = 50

Time spent flushing memtable to disk

RocksDb calls this FLUSH_TIME.

FlushWriteBufferFullMemtableMemoryBytes = 77

Distribution of total memtable memory usage for write-buffer-full flushes.

RocksDb calls this FLUSH_WRITE_BUFFER_FULL_MEMTABLE_MEMORY_BYTES.

FlushWriteBufferManagerMemtableMemoryBytes = 78

Distribution of total memtable memory usage for WBM-triggered flushes.

RocksDb calls this FLUSH_WRITE_BUFFER_MANAGER_MEMTABLE_MEMORY_BYTES.

IngestExternalFilePrepareTime = 71

Time (microseconds) in the "prepare" phase of an IngestExternalFile(s) call (validation and reading/linking the files; does not block writes). One sample per successful call; requires stats level > kExceptTimers.

RocksDb calls this INGEST_EXTERNAL_FILE_PREPARE_TIME.

IngestExternalFileRunTime = 72

Time (microseconds) in the "run" phase of an IngestExternalFile(s) call (work under the DB mutex while writes are blocked). One sample per successful call; requires stats level > kExceptTimers.

RocksDb calls this INGEST_EXTERNAL_FILE_RUN_TIME.

IoDispatcherAsyncReadObservedCompletionMicros = 67

Time (microseconds) from IODispatcher async read submission until completion callback execution.

RocksDb calls this IO_DISPATCHER_ASYNC_READ_OBSERVED_COMPLETION_MICROS.

IoDispatcherAsyncReadPollWaitMicros = 68

Time (microseconds) IODispatcher spends waiting in FileSystem::Poll().

RocksDb calls this IO_DISPATCHER_ASYNC_READ_POLL_WAIT_MICROS.

IoDispatcherAsyncReadPrefetchLeadMicros = 69

Time (microseconds) from async read submission until the block consumer starts polling for completion.

RocksDb calls this IO_DISPATCHER_ASYNC_READ_PREFETCH_LEAD_MICROS.

ManifestFileSyncMicros = 8

RocksDb's MANIFEST_FILE_SYNC_MICROS.

MultigetIoBatchSize = 52

Number of IOs issued in parallel in a MultiGet batch

RocksDb calls this MULTIGET_IO_BATCH_SIZE.

MultiscanBlocksPerPrepare = 66

Distribution of blocks prefetched per MultiScan Prepare()

RocksDb calls this MULTISCAN_BLOCKS_PER_PREPARE.

MultiscanPrepareIterators = 64

MultiScan Prefill iterator Prepare cost

RocksDb calls this MULTISCAN_PREPARE_ITERATORS.

MultiscanPrepareMicros = 65

Total Prepare() latency for MultiScan

RocksDb calls this MULTISCAN_PREPARE_MICROS.

NumFilesInSingleCompaction = 14

RocksDb's NUM_FILES_IN_SINGLE_COMPACTION.

NumIndexAndFilterBlocksReadPerLevel = 53

MultiGet stats logged per level Num of index and filter blocks read from file system per level.

RocksDb calls this NUM_INDEX_AND_FILTER_BLOCKS_READ_PER_LEVEL.

NumLevelReadPerMultiget = 55

Number of levels requiring IO for MultiGet

RocksDb calls this NUM_LEVEL_READ_PER_MULTIGET.

NumOpPerTransaction = 63

Number of operations per transaction.

RocksDb calls this NUM_OP_PER_TRANSACTION.

NumSstReadPerLevel = 54

Num of sst files read from file system per level.

RocksDb calls this NUM_SST_READ_PER_LEVEL.

NumSubcompactionsScheduled = 30

The number of subcompactions actually scheduled during a compaction

RocksDb calls this NUM_SUBCOMPACTIONS_SCHEDULED.

OpenAndCompactDbOpenMicros = 79

Time spent opening the secondary DB inside DB::OpenAndCompact().

RocksDb calls this OPEN_AND_COMPACT_DB_OPEN_MICROS.

PollWaitMicros = 58

RocksDb's POLL_WAIT_MICROS.

PrefetchedBytesDiscarded = 60

Number of prefetched bytes discarded by RocksDB.

RocksDb calls this PREFETCHED_BYTES_DISCARDED.

RateLimiterWaitMicrosRead = 73

Time read requests spent waiting for rate limiter refills.

RocksDb calls this RATE_LIMITER_WAIT_MICROS_READ.

RateLimiterWaitMicrosWrite = 74

Time write requests spent waiting for rate limiter refills.

RocksDb calls this RATE_LIMITER_WAIT_MICROS_WRITE.

ReadBlockCompactionMicros = 11

RocksDb's READ_BLOCK_COMPACTION_MICROS.

ReadBlockGetMicros = 12

RocksDb's READ_BLOCK_GET_MICROS.

ReadNumMergeOperands = 36

Number of merge operands passed to the merge operator in user read requests.

RocksDb calls this READ_NUM_MERGE_OPERANDS.

SstBatchSize = 51

RocksDb's SST_BATCH_SIZE.

SstReadMicros = 17

Time spent in reading block-based or plain SST table

RocksDb calls this SST_READ_MICROS.

SstWriteMicros = 26

Time spent in writing SST files

RocksDb calls this SST_WRITE_MICROS.

SubcompactionSetupTime = 4

RocksDb's SUBCOMPACTION_SETUP_TIME.

TableOpenIoMicros = 9

TIME SPENT IN IO DURING TABLE OPEN

RocksDb calls this TABLE_OPEN_IO_MICROS.

TableOpenPrefetchTailReadBytes = 62

Number of bytes for RocksDB's prefetching contents (as opposed to file system's prefetch) from the end of SST table during block based table open

RocksDb calls this TABLE_OPEN_PREFETCH_TAIL_READ_BYTES.

TableSyncMicros = 5

RocksDb's TABLE_SYNC_MICROS.

WalFileSyncMicros = 7

RocksDb's WAL_FILE_SYNC_MICROS.

WriteRawBlockMicros = 13

RocksDb's WRITE_RAW_BLOCK_MICROS.

WriteStall = 16

RocksDb's WRITE_STALL.

Remarks

Pass one to GetHistogramData(Histogram).

The values are positional in RocksDb's header, so they change between releases when a counter is added or retired. They are generated from the pinned version rather than written out by hand for that reason.

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